cvs version of pthreads

1 files changed, 253 insertions, 251 deletions

diff --git a/pthreads/pthread_cond_destroy.c b/pthreads/pthread_cond_destroy.c
index 34550f08d..40d4a0896 100644
--- a/pthreads/pthread_cond_destroy.c
+++ b/pthreads/pthread_cond_destroy.c
@@ -1,251 +1,253 @@
-/*

- * pthread_cond_destroy.c

- *

- * Description:

- * This translation unit implements condition variables and their primitives.

- *

- *

- * --------------------------------------------------------------------------

- *

- *      Pthreads-win32 - POSIX Threads Library for Win32

- *      Copyright(C) 1998 John E. Bossom

- *      Copyright(C) 1999,2005 Pthreads-win32 contributors

- * 

- *      Contact Email: rpj@callisto.canberra.edu.au

- * 

- *      The current list of contributors is contained

- *      in the file CONTRIBUTORS included with the source

- *      code distribution. The list can also be seen at the

- *      following World Wide Web location:

- *      http://sources.redhat.com/pthreads-win32/contributors.html

- * 

- *      This library is free software; you can redistribute it and/or

- *      modify it under the terms of the GNU Lesser General Public

- *      License as published by the Free Software Foundation; either

- *      version 2 of the License, or (at your option) any later version.

- * 

- *      This library is distributed in the hope that it will be useful,

- *      but WITHOUT ANY WARRANTY; without even the implied warranty of

- *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

- *      Lesser General Public License for more details.

- * 

- *      You should have received a copy of the GNU Lesser General Public

- *      License along with this library in the file COPYING.LIB;

- *      if not, write to the Free Software Foundation, Inc.,

- *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA

- */

-

-#include "pthread.h"

-#include "implement.h"

-

-int

-pthread_cond_destroy (pthread_cond_t * cond)

-     /*

-      * ------------------------------------------------------

-      * DOCPUBLIC

-      *      This function destroys a condition variable

-      *

-      *

-      * PARAMETERS

-      *      cond

-      *              pointer to an instance of pthread_cond_t

-      *

-      *

-      * DESCRIPTION

-      *      This function destroys a condition variable.

-      *

-      *      NOTES:

-      *              1)      A condition variable can be destroyed

-      *                      immediately after all the threads that

-      *                      are blocked on it are awakened. e.g.

-      *

-      *                      struct list {

-      *                        pthread_mutex_t lm;

-      *                        ...

-      *                      }

-      *

-      *                      struct elt {

-      *                        key k;

-      *                        int busy;

-      *                        pthread_cond_t notbusy;

-      *                        ...

-      *                      }

-      *

-      *                      

-      *                      struct elt *

-      *                      list_find(struct list *lp, key k)

-      *                      {

-      *                        struct elt *ep;

-      *

-      *                        pthread_mutex_lock(&lp->lm);

-      *                        while ((ep = find_elt(l,k) != NULL) && ep->busy)

-      *                          pthread_cond_wait(&ep->notbusy, &lp->lm);

-      *                        if (ep != NULL)

-      *                          ep->busy = 1;

-      *                        pthread_mutex_unlock(&lp->lm);

-      *                        return(ep);

-      *                      }

-      *

-      *                      delete_elt(struct list *lp, struct elt *ep)

-      *                      {

-      *                        pthread_mutex_lock(&lp->lm);

-      *                        assert(ep->busy);

-      *                        ... remove ep from list ...

-      *                        ep->busy = 0;

-      *                    (A) pthread_cond_broadcast(&ep->notbusy);

-      *                        pthread_mutex_unlock(&lp->lm);

-      *                    (B) pthread_cond_destroy(&rp->notbusy);

-      *                        free(ep);

-      *                      }

-      *

-      *                      In this example, the condition variable

-      *                      and its list element may be freed (line B)

-      *                      immediately after all threads waiting for

-      *                      it are awakened (line A), since the mutex

-      *                      and the code ensure that no other thread

-      *                      can touch the element to be deleted.

-      *

-      * RESULTS

-      *              0               successfully released condition variable,

-      *              EINVAL          'cond' is invalid,

-      *              EBUSY           'cond' is in use,

-      *

-      * ------------------------------------------------------

-      */

-{

-  pthread_cond_t cv;

-  int result = 0, result1 = 0, result2 = 0;

-

-  /*

-   * Assuming any race condition here is harmless.

-   */

-  if (cond == NULL || *cond == NULL)

-    {

-      return EINVAL;

-    }

-

-  if (*cond != PTHREAD_COND_INITIALIZER)

-    {

-      EnterCriticalSection (&ptw32_cond_list_lock);

-

-      cv = *cond;

-

-      /*

-       * Close the gate; this will synchronize this thread with

-       * all already signaled waiters to let them retract their

-       * waiter status - SEE NOTE 1 ABOVE!!!

-       */

-      if (ptw32_semwait (&(cv->semBlockLock)) != 0) /* Non-cancelable */

-	{

-	  result = errno;

-	}

-      else

-        {

-          /*

-           * !TRY! lock mtxUnblockLock; try will detect busy condition

-           * and will not cause a deadlock with respect to concurrent

-           * signal/broadcast.

-           */

-          if ((result = pthread_mutex_trylock (&(cv->mtxUnblockLock))) != 0)

-	    {

-	      (void) sem_post (&(cv->semBlockLock));

-	    }

-	}

-	

-      if (result != 0)

-        {

-          LeaveCriticalSection (&ptw32_cond_list_lock);

-          return result;

-        }

-

-      /*

-       * Check whether cv is still busy (still has waiters)

-       */

-      if (cv->nWaitersBlocked > cv->nWaitersGone)

-	{

-	  if (sem_post (&(cv->semBlockLock)) != 0)

-	    {

-	      result = errno;

-	    }

-	  result1 = pthread_mutex_unlock (&(cv->mtxUnblockLock));

-	  result2 = EBUSY;

-	}

-      else

-	{

-	  /*

-	   * Now it is safe to destroy

-	   */

-	  *cond = NULL;

-

-	  if (sem_destroy (&(cv->semBlockLock)) != 0)

-	    {

-	      result = errno;

-	    }

-	  if (sem_destroy (&(cv->semBlockQueue)) != 0)

-	    {

-	      result1 = errno;

-	    }

-	  if ((result2 = pthread_mutex_unlock (&(cv->mtxUnblockLock))) == 0)

-	    {

-	      result2 = pthread_mutex_destroy (&(cv->mtxUnblockLock));

-	    }

-

-	  /* Unlink the CV from the list */

-

-	  if (ptw32_cond_list_head == cv)

-	    {

-	      ptw32_cond_list_head = cv->next;

-	    }

-	  else

-	    {

-	      cv->prev->next = cv->next;

-	    }

-

-	  if (ptw32_cond_list_tail == cv)

-	    {

-	      ptw32_cond_list_tail = cv->prev;

-	    }

-	  else

-	    {

-	      cv->next->prev = cv->prev;

-	    }

-

-	  (void) free (cv);

-	}

-

-      LeaveCriticalSection (&ptw32_cond_list_lock);

-    }

-  else

-    {

-      /*

-       * See notes in ptw32_cond_check_need_init() above also.

-       */

-      EnterCriticalSection (&ptw32_cond_test_init_lock);

-

-      /*

-       * Check again.

-       */

-      if (*cond == PTHREAD_COND_INITIALIZER)

-	{

-	  /*

-	   * This is all we need to do to destroy a statically

-	   * initialised cond that has not yet been used (initialised).

-	   * If we get to here, another thread waiting to initialise

-	   * this cond will get an EINVAL. That's OK.

-	   */

-	  *cond = NULL;

-	}

-      else

-	{

-	  /*

-	   * The cv has been initialised while we were waiting

-	   * so assume it's in use.

-	   */

-	  result = EBUSY;

-	}

-

-      LeaveCriticalSection (&ptw32_cond_test_init_lock);

-    }

-

-  return ((result != 0) ? result : ((result1 != 0) ? result1 : result2));

-}

+/*
+ * pthread_cond_destroy.c
+ *
+ * Description:
+ * This translation unit implements condition variables and their primitives.
+ *
+ *
+ * --------------------------------------------------------------------------
+ *
+ *      Pthreads-win32 - POSIX Threads Library for Win32
+ *      Copyright(C) 1998 John E. Bossom
+ *      Copyright(C) 1999,2005 Pthreads-win32 contributors
+ * 
+ *      Contact Email: rpj@callisto.canberra.edu.au
+ * 
+ *      The current list of contributors is contained
+ *      in the file CONTRIBUTORS included with the source
+ *      code distribution. The list can also be seen at the
+ *      following World Wide Web location:
+ *      http://sources.redhat.com/pthreads-win32/contributors.html
+ * 
+ *      This library is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU Lesser General Public
+ *      License as published by the Free Software Foundation; either
+ *      version 2 of the License, or (at your option) any later version.
+ * 
+ *      This library is distributed in the hope that it will be useful,
+ *      but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *      Lesser General Public License for more details.
+ * 
+ *      You should have received a copy of the GNU Lesser General Public
+ *      License along with this library in the file COPYING.LIB;
+ *      if not, write to the Free Software Foundation, Inc.,
+ *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "implement.h"
+
+int
+pthread_cond_destroy (pthread_cond_t * cond)
+     /*
+      * ------------------------------------------------------
+      * DOCPUBLIC
+      *      This function destroys a condition variable
+      *
+      *
+      * PARAMETERS
+      *      cond
+      *              pointer to an instance of pthread_cond_t
+      *
+      *
+      * DESCRIPTION
+      *      This function destroys a condition variable.
+      *
+      *      NOTES:
+      *              1)      A condition variable can be destroyed
+      *                      immediately after all the threads that
+      *                      are blocked on it are awakened. e.g.
+      *
+      *                      struct list {
+      *                        pthread_mutex_t lm;
+      *                        ...
+      *                      }
+      *
+      *                      struct elt {
+      *                        key k;
+      *                        int busy;
+      *                        pthread_cond_t notbusy;
+      *                        ...
+      *                      }
+      *
+      *                      
+      *                      struct elt *
+      *                      list_find(struct list *lp, key k)
+      *                      {
+      *                        struct elt *ep;
+      *
+      *                        pthread_mutex_lock(&lp->lm);
+      *                        while ((ep = find_elt(l,k) != NULL) && ep->busy)
+      *                          pthread_cond_wait(&ep->notbusy, &lp->lm);
+      *                        if (ep != NULL)
+      *                          ep->busy = 1;
+      *                        pthread_mutex_unlock(&lp->lm);
+      *                        return(ep);
+      *                      }
+      *
+      *                      delete_elt(struct list *lp, struct elt *ep)
+      *                      {
+      *                        pthread_mutex_lock(&lp->lm);
+      *                        assert(ep->busy);
+      *                        ... remove ep from list ...
+      *                        ep->busy = 0;
+      *                    (A) pthread_cond_broadcast(&ep->notbusy);
+      *                        pthread_mutex_unlock(&lp->lm);
+      *                    (B) pthread_cond_destroy(&rp->notbusy);
+      *                        free(ep);
+      *                      }
+      *
+      *                      In this example, the condition variable
+      *                      and its list element may be freed (line B)
+      *                      immediately after all threads waiting for
+      *                      it are awakened (line A), since the mutex
+      *                      and the code ensure that no other thread
+      *                      can touch the element to be deleted.
+      *
+      * RESULTS
+      *              0               successfully released condition variable,
+      *              EINVAL          'cond' is invalid,
+      *              EBUSY           'cond' is in use,
+      *
+      * ------------------------------------------------------
+      */
+{
+  pthread_cond_t cv;
+  int result = 0, result1 = 0, result2 = 0;
+
+  /*
+   * Assuming any race condition here is harmless.
+   */
+  if (cond == NULL || *cond == NULL)
+    {
+      return EINVAL;
+    }
+
+  if (*cond != PTHREAD_COND_INITIALIZER)
+    {
+      ptw32_mcs_local_node_t node;
+      ptw32_mcs_lock_acquire(&ptw32_cond_list_lock, &node);
+
+      cv = *cond;
+
+      /*
+       * Close the gate; this will synchronize this thread with
+       * all already signaled waiters to let them retract their
+       * waiter status - SEE NOTE 1 ABOVE!!!
+       */
+      if (ptw32_semwait (&(cv->semBlockLock)) != 0) /* Non-cancelable */
+	{
+	  result = errno;
+	}
+      else
+        {
+          /*
+           * !TRY! lock mtxUnblockLock; try will detect busy condition
+           * and will not cause a deadlock with respect to concurrent
+           * signal/broadcast.
+           */
+          if ((result = pthread_mutex_trylock (&(cv->mtxUnblockLock))) != 0)
+	    {
+	      (void) sem_post (&(cv->semBlockLock));
+	    }
+	}
+	
+      if (result != 0)
+        {
+          ptw32_mcs_lock_release(&node);
+          return result;
+        }
+
+      /*
+       * Check whether cv is still busy (still has waiters)
+       */
+      if (cv->nWaitersBlocked > cv->nWaitersGone)
+	{
+	  if (sem_post (&(cv->semBlockLock)) != 0)
+	    {
+	      result = errno;
+	    }
+	  result1 = pthread_mutex_unlock (&(cv->mtxUnblockLock));
+	  result2 = EBUSY;
+	}
+      else
+	{
+	  /*
+	   * Now it is safe to destroy
+	   */
+	  *cond = NULL;
+
+	  if (sem_destroy (&(cv->semBlockLock)) != 0)
+	    {
+	      result = errno;
+	    }
+	  if (sem_destroy (&(cv->semBlockQueue)) != 0)
+	    {
+	      result1 = errno;
+	    }
+	  if ((result2 = pthread_mutex_unlock (&(cv->mtxUnblockLock))) == 0)
+	    {
+	      result2 = pthread_mutex_destroy (&(cv->mtxUnblockLock));
+	    }
+
+	  /* Unlink the CV from the list */
+
+	  if (ptw32_cond_list_head == cv)
+	    {
+	      ptw32_cond_list_head = cv->next;
+	    }
+	  else
+	    {
+	      cv->prev->next = cv->next;
+	    }
+
+	  if (ptw32_cond_list_tail == cv)
+	    {
+	      ptw32_cond_list_tail = cv->prev;
+	    }
+	  else
+	    {
+	      cv->next->prev = cv->prev;
+	    }
+
+	  (void) free (cv);
+	}
+
+      ptw32_mcs_lock_release(&node);
+    }
+  else
+    {
+      ptw32_mcs_local_node_t node;
+      /*
+       * See notes in ptw32_cond_check_need_init() above also.
+       */
+      ptw32_mcs_lock_acquire(&ptw32_cond_test_init_lock, &node);
+
+      /*
+       * Check again.
+       */
+      if (*cond == PTHREAD_COND_INITIALIZER)
+	{
+	  /*
+	   * This is all we need to do to destroy a statically
+	   * initialised cond that has not yet been used (initialised).
+	   * If we get to here, another thread waiting to initialise
+	   * this cond will get an EINVAL. That's OK.
+	   */
+	  *cond = NULL;
+	}
+      else
+	{
+	  /*
+	   * The cv has been initialised while we were waiting
+	   * so assume it's in use.
+	   */
+	  result = EBUSY;
+	}
+
+      ptw32_mcs_lock_release(&node);
+    }
+
+  return ((result != 0) ? result : ((result1 != 0) ? result1 : result2));
+}